Interlocking system for railroads



April 5, 1932. J. c LINDNER INTERLOCKING SYSTEM FOR RAILROADS Filed Aug. 16, 1929 NVENTOR BY Q Mflk @ATTORNEY m fill Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE TDHN C. LINIDNER, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK INTERLOCKING SYSTEM FOR RAILROADS Application filed August 16, 1929.

source of energy and neutral operating circuits.

In one type of electric interlocking system for railroads, to which the present inventlon more particularly relates, the switches, mg-

in nals, or other traflic controlling devices are operated from a central battery, or other source of current, located in the tower, over neutral circuits, energized and ale-energized by operation of the corresponding control 1.- levers. In this type of system a cross between operating wires may occur and tend to cause operation of a switch or a signal out of correspondence with its control lever; and since this may occur after a train has accepted a signal, and even while it is moving over the switch points, it is important to provide suitable cross protection means for opening the operating circuit for a switch, whenever such a cross occurs as would tend to operate at that switch.

Such cross protection devices, operable in accordance with the direction of current flow-' ing, have been proposed and are commonly used for this purpose, but have the d1sad- If vantage that they are normally inactive and do not operate except when a cross occurs, or when specially tested, with the result that such cross protection devices may get out of order, and their inoperative condition not be 3?? detected for some time.

In accordance with the present invention, it proposed to provide a cross protection device which is operated upon each operation of the switch machine, or similar trafiic controlling device, and which must respond on each operation of the switch machine in order to obtain an indication for the control lever. More specifically, this invention contemplates a cross protection device, operated upon each operation of the switch machine by dynamic indication current, which actuates the indication mechanism for the lever, and which is automatically restored when the indication mechanism is actuated.

Various other characteristic features and Serial No. 386,264.

advantages of the invention will be in part apparent, and in part pointed out as the description progresses.

The accompanying drawing shows in a simplified and diagrammatic manner one specific embodiment of the invention applied to a well known electric interlocking system of the dynamic indication type.

Referring to the accompanying drawing, the invention has been shown applied to a single switch, shown diagrammatically and designated TS. The points of this switch TS are connected to and operated by an electric switch machine of the type shown and described, for example, in a patent to Winthrop K. Howe, No. 1,466,903, dated September l, 1923. This switch machine, as more fully shown and described in said Howe patent, comprises a motor, having an armature A and field F, which operates suitable gearing and mechanism for locking and throwing the switch points. This switch machine includes pole-changer contacts, shown conventionally and designated PC, which element comprises contact blocks 5 and 6 cooperating with pairs of contact fingers or springs 78 and 9-10 respectively. With the switch points in the normal position and locked, the contact blocks 5 and 6 engage the pairs of contacts 7 and 8; and when the switch machine is in the reverse position and locked, these contact blocks 5 and 6' are operated to the other extreme position to engage the other pairs of contacts 9 and 10.

The operation of this switch machine is controlled by a suitable manually operable lever L, provided with the usual indication mechanism released by the energization of an indication magnet I. Associated with this indication magnet I is a safety magnet S. The lever L is provided with a cam slot 11 which cooperates with a roller 12 so as to raise and lower the tappet bar 13 of the usual mechanical interlocking between the levers.

The lever L is connected to and operates contactblocks 14-, 15 and 16 engageable with pairs of contact fingers 1722. The lever L has the usual four significant positions, full normal, full reverse, normal indication, and reverse indication. The contact blocks 14 and engage the contact springs and 21 in the full normal and in the normal inclicat-ion position. The contact block 16 engages the contact springs 22 in the normal indication position only. Similarly, the contact blocks 14 and 15 engage the contact springs 17 and 18 in the reverse indication and full reverse positions, and the contact block 16 engages the contact springs 19 in the reverse indication position-only.

Also associated with the lever L is an in-' dication selector, of the type shown and described, for example, in the patent to inthrop K. Howe, No. 1,550,611, dated August 18, 1925. This indication selector IS comprises normal and reverse operating coils 23 and 24 forshifting'a contact arm 25-to its extreme normal position shown, or to the reverse dotted. position, when these respective coils 23 and 24 are energized. The movement of this contact arm 25 connects a stationary contact 26 with contacts 27 and 28 alternately in the normal and reverse positions, respectively.

These various parts and devices associated with the lever L, with the exception of the contact block 16 and springs 19 and 22, and

ance with'this invention, comprises acontact finger or armature 31, actuated from its normal position shown by energization of operating coil 32, to the other extreme position, indicated by dotted lines. The energization of the reset coil 33 restores the contact" finger 31 to the normal position. This contact finger 31 is preferably provided with a toggle-spring arrangement, or other suitable means, such as shown in the patent to'Winthrop K. Howe, No; 1,550.611, above mentioned, so as to be held in either extreme position, in engagement with the stationary contacts indicated by arrows, when caused to assume that position by the energization of the respective coils and 33.

For the purpose of manually restoring the cross protection device GP, when it is operated by a cross, a reset switch BS is provided havin normally open and normally closed contacts, indicated by arrows.

Ao'complete system, embodying the inven-r tion, would also include various other well known devices, such as electric lever locks, lever lights, time releases and the like, in accordance with established interlocking practice; but no attempt has been made to show these auxiliary devices which would be employed in a practical application of the invention.

Operati0n.The parts and circuits are shown in the accompanying drawing in the normal position or condition, corresponding to the lever L and the switch machine SM in the normal positions.

' To operate the switch machine to the reverse position, the operator pulls out the lever L, to the reverse indication position, assuming: that the'mechanical interlocking permits such movement of the tappet bar 13. This establishes a reverse operating circuit for the switch machine which maybe traced as follows :From the battery B, wire 34, reset switch RS normal, wires 35, 36 and 37, safety magnet S, wire 38, contact springs 17 and contact block 14, wire 39, reverse operating wire R, pole-changer contacts 57, wire 40, motor field ,F, wire 41, contacts 68, wires 42 and 43, motor armature A, common return wire C, through the contact finger 31 of the cross protection device GP, and'wires 44 and 45'back to the battery B.

The current thus applied to the armature and field of the switch machine motor,;causes the switch machine to complete its operating cycle of unlocking, throwing the switch points to the reverseposition, andlocking up again; and when this operation is completed, the pole-changercontact blocks 5 and 6 are shifted from the normal position to the reverse-position, thereby establishing an indication circuit, which is energized by the current generated dynamically by the continued rotation of the armature ofthe motor, in the usual and well known way, this indication circuit being traced. as follows: Starting at the common return wire C,armature A, wire 43, pole-changer contacts 610, motor field F, now reversed with respect to the armature,

dotted reverse position. Also, this current,v

flowing through the operating coil 32, of the crossprotection device'CP, shifts its contact finger 31 from the normal position to the reverse dotted position. This establishes a circuitfor energizing the indication magnet I, which may be traced as follows: Conn mencing at B, wire 34, reset switch BS normal, wires 35 and 51, indication mag'netl,

luv

wire 52, contacts 26-25-28 of the indication selector IS, wire 53, contact springs 19 and contact block 16 of the lever, wires 54 and 55, contact finger 31 of the cross protection device GP in the reverse position, and wires 44. and back to the battery B.

This energization of the indication magnet I trips indication mechanism associated with the lever L, in the usual way, permitting the operator to move the lever to the full reverse position.

When the indication magnet I is energized, the closing of its contact 30 establishes a circuit for the restoring coil 33 of the cross protection device GP, said circuit being as 't'ollows :--Startin at the battery B, wire 34;, switch RS normal, wires 35, 36 and 56, contact 30, wires 57 and 58, restoring coil 33, and wires 59 and 45 back to the battery B. This energization of restoring coil 33, after the dynamic indication current in the operating coil 32 has died down, shifts the contact finger 31 back to the normal position shown,

breaking at the same time the energizing circuit tor the indication magnet I, and permitting the contact 30 to open.

The operation of moving the switch from the reverse position back to the normal position involves the same sequence of operation of the various parts; and the normal operating and indication circuits being analogous to those already traced, need not be described in detail.

in electric interlocking systems of the type described, it is important that the cross protection device be able to respond and prevent improper operation of the switch machine, out of correspondence with its control lever, in the event of a cross between the two open sting wires of the switch machine, or such other cross as tends to cause operation of the switch machine. Such cross protection is desirable, even though the well known scheme of controlling the signals by an SS relay is employed, because after a train has accepted a signal, and while it is travelling over the switch, it is important to protect the switch machine against improper operation by crosses.

To explain the cross protection ailorded by this system, assume that a cross is applied between the two operating wires N and R, as indicated at 60. Such a cross, since the normal operating wire N is connected to the battery through the lever contacts M QO, applies current to the reverse operating wire R and tends to operate the switch machine to the reverse position, the same as if the lever were operated to the reverse position. At the same instant that operating current is thus applied to the switch machine, how ever, current is supplied to the operating coil 32 of the cross protection device C]? over the reverse operating wire R, lever contacts 15-21, wire 61, normal coil 23 of the indication selector IS, wires 62 and 49, operating coil 32, and wire to the common return wire 0, and thence to the battery B.

This current through the operating coil 32 moves the contact finger 31 to the dotted position, breaking the connection from the common return wire G to the battery B, and in terrupting the flow of operating current to the switch machine. In other words, when the switch machine is at rest, current applied to the next operating wire, due to a cross, finds a path back to the battery B through the operating coil 32 of the cross protection device GP, as well as through the motor of the switch machine, with the result that the device CP operates the instant such a cross occurs to break the circuit for operating current to flow through the switch machine mo tor. The cross protection device OP is preferably so designed that its contact finger 31 direction of flow of current, as now commonly used. If desired, however, a polarized crossprotection device may be employed; and in this case, since this device is supposed to respond to currents due to crosses, as well as to dynamic indication currents, the polechanger contacts PC and their connections to the motor and armature of the switch machines should be so arranged, as shown, so that the field of the motor is reversed with respect to the armature, rather than the opposits, in order that the dynamic indication current may flow in the same direction through the cross protection device as the current resulting from a cross.

After the cross protection device GP has been operated by a cross in the manner described, it is restored to its normal position by the reset button RS, which is operable to close an energizing circuit through the restoring coil 33, from battery B, wire 34, switch BS in its operated position, wires 63 and 58, restoring coil 33, wires 59 and l5 back to the battery B. It should be noted that when the switch BS is operated, it breaks the connection between the battery 13 and the lever contacts, so that power can not be applied to the switch machine. This prevents the reset switch RS being accidentally or carelessly left in its actuated position, and assures that it will be returned to its normal position after each manual operation.

From the foregoing, it will be noted that the cross protection device CP is operated upon each operation of the switch machine, and must actually move its contact finger 31, in order to give an indication to release the leverz In this way the operative condition of-thecross protectionsdeviceTGP is checked at the end'ofeach operation, and it is assuredwhich armature is urged in opposite direc-- tions by coils I and S, is in engagement with the core of the safety magnet S the magnetic effect due to'the magnet S dominates. The indication selector IS responds to the dynamic indication current and closes normal and reverse contacts in series with the lever contacts 1619 and 1 622, included in the energizing circuit for the indication magnet I, so that this indication selector IS and the lever must be in corresponding positions before the indication magnet I can be energized.

The particular arrangement and combination of circuits and devices shown and describedis-susceptible of considerable modification and adaptation, without departing from the invention.

What I claim is 1. In an electric interlocking system of the type described, a lever; an indication magnet; across protection device operated by dynamic indicationcurrent, for controlling the energization of said indication magnet; and means i for restoring said cross protection device to normal, when said indication magnet is energized.

In'an electric interlocking system of the.

type described, aswitch machine, a cross protection device having an operatingcoil included in the circuit of said switch machine and having a restoring coil, an indication magnet, and a circuit for said restoring coil closed by the energization of said indication magnet.

3. In an electric interlockin system of the type described, a switch machine,a source of current for operating said switch machine, a return connection from the switchmachine to said source, an indication circuit closed aftereach operation of the switch machine and while it is at rest, a control lever and indication mechanism therefor, and a crossprotection device operated by a flow of indication current in said circuit and also by current from said-source applied to said cir-' storedto nor-malupon operation of the indi cation mechanism.

nseassa 4. An interlocking system of the type described characterized by an indication mechanism for governing locking of acontrol lever, a'cross-protectiondevice-for protecting atraflic controlling device controlledby: said lever against operation by foreign current, and'circuits and devices for'controlling said indication mechanism by sai d'cross-protection device and controlling said cross-protection device by said indication mechanism.

5. An electric interlocking system of the type described comprising, incombination with asswitch machine-and indication circuits therefor, closed after eachnormal operationf the switclrinac'hine, a cross protection device included insaid circuit and operable by current flowing in either direction therein, and means for restoringsaid device, said means being responsive to indication current flowing in said circuit but not to'operating' current.

(3. In an interlocking system, the combination with a switch machine and a=lever for controlling the same, of two control Wires used separately in combination with a commonreturn wire to constitute operating circuits for operating said switch machine in opposite directions, said operating circuits being closed when said lever and switch machine are out of correspondence, two indication circuits each including'one of said control wires and saidcommoirwire and including a cross-protection relay, an indication magnet normally locking said lever controlled by said cross protection relay, and means'controlled by said magnet for returning said cross-protection relay backto normal;

' 7. In an interlocking'system, the combination with a switch machine and a' lever for controlling the same, of two control wires used separately in combination with a common return wire to constitute operating cir-' ing a cross-protection relay, an indicationmagnet normally locking said'lever controlled by said cross-protection relay, means concontrolled by saidmagnet for returning said cross-protection relayback to normal, and manually operable means for returning said cross-protection relay to normal;

8; In an interlocking system, the combination with a switch machine and alever for controlling the same, of two control wires used separately in combination with a common return wire'to constitute operating circuits for operating said switch machine in opposite directions, said operating'circuits being closed when said lever and switch ma chine are out of correspondence',-two indication circuits each including one of said' control wires and said common Wire and including a cross-protection relay, a two coil two position indication device having one coil included in one of said indicating circuits and its other coil included in said other indicating circuit only if said cross-protection relay is in its abnormal position, an indication magnet energized only if said lever and said indicating device assume corresponding posi- 19 tions, and means controlled by said indication magnet for restoring said cross-protection relay to normal.

9. In an interlocking system, the combination with a switch machine and a lever for controlling the same, of two control Wires used separately in combination with a common return wire to constitute operating circuits for operating said switch machine in opposite directions, said operating circuits Q0 being closed when said lever and switch machine are out of correspondence, two indication circuits each including one of said control wires and said common wire and including a cross-protection relay, a two coil two 95 position indicating device having one coil included in one of said indicating circuits and its other coil included in said other inclicatingcircuit only if said cross-protection relay is in its abnormal position, an indication magnet energized only if said lever and said indicating device assume corresponding positions, means controlled by said indication magnet for restoring said cross-protection relay to normal, and manually operable means for returning said cross-protection relay to normal.

In testimony whereof I affix my signature.

JOHN G. LINDNER. 

